The present invention relates to a new and improved apparatus for maintaining spinal elements in a desired spatial relationship. More specifically, the present invention relates to an apparatus for maintaining cervical vertebrae of a spinal column in a desired spatial relationship.
A known apparatus for maintaining spinal elements in a desired spatial relationship includes a plate having a longitudinally extending slot extending along one side of the longitudinal axis of the plate. A circular opening for receiving a fastener, such as a screw, is located adjacent the slot on the other side of the longitudinal axis. The slot defines a plurality of locations for receiving another screw. The plate is bent about its longitudinal axis so that the slot and the circular opening extend through the plate at an angle to each other.
The center of one of the plurality of locations is aligned with the center of the circular opening, i.e., the centers lie in a plane extending perpendicular to the longitudinal axis of the plate. Thus, the screw extending through the circular opening and the screw extending through the slot may strike each other in the spinal element when the plate is attached to the spinal element.
To attach the plate to the spinal column, a first screw is placed through the slot in the plate and threaded into a spinal element a small amount. The plate is then moved so that the circular opening is in a desired position. A second screw is placed through the circular opening and threaded into the spinal element to fixedly attach the plate to the spinal element. The first screw extending through the slot is then fully driven into the spinal element to further fix the plate to the spinal element. While the second screw is being threaded into the spinal element the plate can rotate relative to the first screw and move out of the desired position.